The reactor was followed by two washing bottles,
each of them containing 500 mL of acidified 2e5% KI solution for
determining unused ozone. The bubble column reactor was filled
with 2000 mL of dye solution before each run. Oxygen gas was
allowed to pass through the ozonizer where ozone formation takes
place. The outlet stream from the ozonizer containing O3 and O2
mixture was allowed to pass through Tygon tubing connected to
the bottom of the bubble column. The gas flow rate was controlled
by a needle valve and was measured by air flow meters. The
temperature was fixed at 20 1 C during all experiments. The pH
of wastewater was adjusted to the desired level with Merck quality
analytical grade 0.1 N NaOH and H2SO4.